1. Field of the Invention
The present invention relates to a digital camera, electronic equipment with a photographing function, such as a cellular phone, and so on. In particular, it relates to a recording process of image data.
2. Description of the Related Art
In a digital camera, image data is generally subjected to a compression process in accordance with the JPEG. Concretely, luminance data and color difference data are subjected to a sampling process, and a DCT (Discrete Cosine Transform) process and a Huffman coding process are carried out on the sampled luminance and color difference data. Consequently, compressed image data is generated. The ratio of sampling frequencies associated with the luminance and color difference data is predetermined.
In a printer system, to raise the compression factor, a sampling frequency of a low-resolution image is set to a high frequency, whereas a sampling frequency of high-resolution image is set to a low frequency. However, this compression process is not preferable to a digital camera. An effective compression process suitable for the camera is needed.